This invention relates generally to variable area or geometry aerodynamic or airfoil structures, and, more particularly to airfoils capable of variation between fully deployed, aerodynamic functional configurations and contraction by spanwise elements, subsequently folded to the stowed position.
Variable area geometric airfoils have been utilized in a number of aerodynamic vehicles, principally for the purpose of effective stowage by virtue of compaction and of improvement of aerodynamic efficiency under specific flight conditions. It is well known, for example, to provide telescoping airfoils that may be extended in the spanwise direction from a compacted stowage configuration for flight purposes. It is also known to employ various forms of pivoted wing configurations for purposes of stowage or various operations. Apart from the familiar wing structure used on carrier based aircraft, few of such structures have either proved practical or met the requirements of retraction in the chordwise direction by a plurality of spanwise elements.
Such a stowable configuration is extremely important since it is capable of meeting many of the design configurations of modern aircraft such as (1) satisfying the requirements of not substantially increasing structural weight and (2) meeting aircraft operative limitations while remaining reliable in operation. Past variable wing configurations have generally imposed excessive weight penalties, or afforded inadequate structural properties, or required complex and cumbersome retraction mechanisms which were less than reliable during operating conditions.